Donor DNA taken up by Streptococcus pneumoniae competent for genetic transformation is converted into single strand fragments a few microns long, which eventually recombine with the cell chromosome. These fragments are found in a specific complex with a small protein that is synthesized only as cells develop the ability to take up DNA. At maximum competence, protein synthesis is limited to this and about 11 other principal proteins. The proposed research will apply biochemical techniques to characterize and isolate these other competence-specific proteins, and to investigate their possible roles in genetic recombination. A direct genetic approach will be taken to identify the role of these proteins in competence and transformation: an appropriate selection procedure will be developed to establish a collection of competence-defective mutations, and a screen based on iso-electric focussing will be applied to identify those competence-specific proteins encoded by genes essential for competence.